Rotary fan and pump.



No. 679,499. Patented July 30, I901. S. C. DAVIDSON. ROTARY FAN ANDPUMP.

(Application filed Nov. 20, 1899.) (No Model.) 5 She0i8-$he9l I.

INVENTOR:

By A zzomeys, mew

WITNESSES:

464 flu No. 579,499. Patented July 30, mm.

s. c. DAVIDSON. ROTARY FAN AND PUMP.

(Apulicntion filed Nov. 20, 1899.) (No Model.)

5 Shaets-$heat 2.

INVENTOR:

WITNESSES:

By Aim mas, (Rm. @m

Patented July 30, l90l.

8. C. DAVID SDN. ROTARY FAN AND PUMP.

(Application filed Nov. 20, 1899.) (No Model.) 5 Sheats-$heat 3.

INVENTOR:

WyIgLNESSES:

By Afzameys,

.ah kom 6" m: 340mm PEYERS couwooro-umo. wsmnuron. n. cy

No. 679,499. Patented July 30, IQDI.

S. C. DAVIDSON.

ROTARY FAN AND PUMP.

(Application 2115:! Nov. 20, 1899.)

5 Sheets-Sheet 4.

(No Model.)

WITNESSES:

By Attorneys, x %z4M/' W@.'rzmu 6 Th2 uoams PETERS co, mmcuumo.WASNINGTOM, n. c.

No. 679,499. Pdtentdd July 30, mm.

s. c. DAVIDSON.

ROTARY FAN AND PUMP.

(Application filed Nov. 90, 1899.)

5 Sheets-Sheet 5,

(No Model.)

INVENTOR:

By Atzorneys,

WITNESSES:

UNTTED STATES PATENT OFFICE.

SAMUEL CLELAND DAVIDSON, OF BELFAST, IRELAND.

ROTARY FAN AND PUMP.

SPECIFICATION forming part of Letters Patent N 0. 679,499, dated July30, 1901.

Application filed November 20, 1899. Serial No. 737,597. (No model.)

To in whom it may concern.-

Be it known that I, SAMUEL CLELAND DA- VIDSON, a subject of the Queen ofGreat Britain, and a resident of Belfast, Ireland, have invented certainnewand useful Improvements in Centrifugal Fans and Pumps, of which thefollowing is a specification.

This invention has reference to rotary fans or pumps in which the fluidoperated on is taken in axially and discharged circumferentially; and itrelates to centrifugal fans or pumps in which the blades carry the fluidwith them in their rotation, and thereby throw it outward by centrifugalforce, as distinguished from propeller fans or pumps in which the bladesact upon the fluid with a wedging action, pushing it from them withoutmaterially rotating it.

In this specification the word fan is understood as including a pump.The word axially means in a direction coincident with or parallel withthe axis of rotation. The word blades is used to indicate the vanes orwings which impart motion to the fluid. The expression intakechamber isemployed to indicate a chamber or space inclosed within the series ofblades. The word eye is used to designate the inlet-opening in thecasing or stationary member of the fan, through which opening oropenings the fluid enters the intake-chamber. The depth of the blades istheir width measured radially from the inner to the outer edge, thelength of the blades is their axial measurement, and the ports are theintervening spaces between the blades.

In my application, Serial No. 691395, filed September 21, 1898, I haveshown a fan the rotary member of which is constructed with numerouselongated blades arranged in sub stantially drum form, being extended inapproximately axial direction, so as to inclose within them a relativelylarge and practically unobstructed intake-chamber, said blades intransverse section being arranged relatively to the axis and directionof rotation to carry the fluid with them rotatively and discharge ittangentially and said rotary member being so mounted as to permit thetangential escape of the fluid discharged from its blades. My presentinvention relates to a fan of this type and provides a rotary memberwhich is open at both ends. When combined with a casing or stationarymember, the latter is preferably formed with diametrically oppositeopenings in alinement with the open ends of the rotary member of thefan, so that the fluid operated on may enter the intake-chamber fromboth endsthereof and be discharged through the circumferential portswhich are formed by the spaces between the blades. A central hub ispreferably provided which is fixed to the driving-shaft, and the bladesare provided with an annular support which preferably engages the edgesof the blades at their ends and is connected to such hub by suitablespokes or stays, so that the blades are centrally supported. Such spokesor stays are made adjustable, so that the blades may be drawn intoconcentric relation with the hub. The blades are best made of sheetmetal and are elongatedthat is to say, their length approximates at theleast three times their depth and being preferably as much as six ormore times their depthit being preferable to make them as narrow orshallow as practi cable consistent with strength of construc tion.Preferably their inner and outer edges are substantially parallel toeach other. The blades must be so shaped relatively to the axis anddirection of rotation as to carry the fluid with them in their rotationin order to throw it outward by centrifugal force, whereby it isdischarged tangentially. To this end the blades are shown as formed ascurved plates, with their outer edges turned forward in the direction ofrotation. The particular form of blades is, however, immaterial to mypresent invention. The blades are so numerous as to follow each other inclose sue cession, being spaced apart preferably a distanceapproximating two-thirds of their radial depth, or it may be as much astwice the full depth of the blades. The drum-like arrangement of theblades is such as to inclose within them an intake-chamber, whichpreferably is approximately cylindrical and which is of large dimensionsas compared with fans heretofore existingthat is to say, its diameterapproximates at the least to four times the radial depth of theindividual blades and in the preferred proportions is about fivesixthsof the external diameter. of the series of blades, and its length oraxial dimension approximates at least three times the depth of theindividual blades and in the preferred proportions is approximately sixor more times such depth. The rotary member of the fan is suitablymounted to permit the tangential escape of the fluid discharged from itsblades. If not incased, this fluid can freely escape from it in alldirections. If inclosed in a casing, the latter must be so constructedas to permit the tangential escape of the finidas, for example, byforming the casing of the usual snail shape, with a tangential outletbeyond the periphery of the rotary member. In my preferred constructionthe intake ends of the blades are open to the inflowing fluid, so thatthe fluid may flow axially into the intake ends of the ports. In thiscase I make the eye or eyes in the casing leading to the fan of adiameter equal, or approximately so, to the full outer diameter of thedrum-shaped series of blades, whereby the volume of fluid which will bepropelled through the fan for a given diameter and speed of revolutionmay be proportionately increased withoutloss of velocity in the flow ofthe fluid.

Fans or pumps constructed according to my present invention may beemployed with any fluids, either gaseous or liquid-as, for in stance,with air or water.

In the drawings, in which I have shown several forms of my invention,Figure 1 is a vertical mid-section of the preferred formof Y myinvention, taken on the line 1 1 in Fig. 2 1

and showing the rotary member mounted in a suitable casing.

- takenon the line 2 2 in Fig. 1. The remaining figures show the rotarymember of the fan removed from the casing and on a larger i Fig. 3 is amid cross-section, and Fig. 4 is diametrical section, of theconstruction I shown in Figs. 1 and 2. Fig. 5 is an end view,

scale.

and Fig. 6 is a diametrical section, of a modified construction in whichthe fan-blades are supported at two points inwardly of their ends byencircling rings. Fig. 7 is an end the blades. 10 is a diametricalsection, of a modification in which the ports between the blades areclosed.

In the drawings, A is the rotary member or I are greatly increased.

Fig. 2 is a vertical section The length of the number is employed in agiven diameter of fan. They may be curved, as shown, and their ends maybe rounded, although these features are not essential to my presentinvention. The blades inclose an intake-chamber A, of relatively largediameter as compared with the common form of fan. The provision of arelatively large intake-chamber in connection with shallow bladesfollowing each other at frequent intervals is a distinctive feature ofthe form of fan shown. In fans as ordinarily constructed employingblades of great radial measurement supplementary vibrations and eddiesare set up, which reduce the eficiency of the fan. In those fans also inwhich the blades are extended inwardly to or near the axis the bestefficiency is not obtained. By providing a relatively largeintake-chamber practically unobstructed by the projection into it ofblades or other parts and by employing blades which extend as shortadistance from the periphery of the fan inward as is consistent withstrength of construction the said supplementary vibrations and eddiesare minimized and the velocity and volume of fluid discharged for agiven speed of revolution I prefer to make the intake ends of the bladesopen or unobstructed, so as to form open-ended ports between them, asshown in Figs. 1 to 8. \Vith this construction of fan I prefer to formthe eye or eyes of the casing (when one is used) of equal diameter tothat of the fan periphery. The fluid may thus enter freely through sucheyes into the open ends of the ports.

The blades are shown in Figs. 1 to a as fixed upon the inner sides oftwo annular supports or rings E E, which encircle the blades at theirends, the latter being secured to the rings by rivets passing throughthe rings and through flanges 1), formed on the ends of the blades. Anyother suitable means of fastening the blades to the supports may beemployed. The latter are preferably formed with perpendicular flanges 6,so as to stiffen them view, and Fig. 8 a diametrical section, of amodification in which the blades are supported upon two rings arrangedinteriorly of Fig. 9 is an end view, and Fig. 1

and makethem better resist the strains of use.

The fan is connected to its hub F by stays G, of which eight are shown,and which at their inner ends are suitably fastened to the hub,preferably by screws, as shown. At their outer ends the stays G engagethe rings or sup-ports E E, preferably by passing through plates orbrackets H, fixed to said supports, being secured to said brackets bynuts g. The rotary member or fan may be trued or drawn to concentricform by the nuts g during manufacture or subsequently in case the rotaryfan or any part thereof assumes a position eccentric to itsoperatingshaft. By the construction just described the rotary fan issupported in a very strong and-the tendency to distortion is to a largeextent avoided. While fans of this construction may be operated withgood results within a casing with a single eye, I prefer that the intaketo the rotary fan shall be through both ends thereof. I therefore formthe casing D with two eyes (Z cl, which are oppositely arranged and areof a diameter equal to that of the intake-chamber, or preferably whenthe ports between the blades of the fan are open at their ends the eyesmay advantageously be of the full exteriordiameter of the fan. Theseports may be closed at their ends, as shown in Figs. 9 and 10; but inthat case the efficiency of the fan is somewhat decreased. Each of theeyes d is preferably provided with a mouth or funnel d for directing theairinto the eyes. The shaft-bearings I may be constructed and supportedin any suitable way. Preferably they are connected to the mouths d bysuitable braces J, as shown in Fig. 2. This construction of bearings isset forthin myPatentNo. 630,529, granted August 8, 1899.

The preferred form of my invention, where the fan takes in air at bothends of the intake-chamber, has the important advantage of practicallyincreasing the intake-opening with a given diameter of fan, and hencethe volumetric efficiency of the fan may be increased by increasing itslength, the diameter remaining the same.

In Figs. 5 and 6 I have shown a modified form of my invention in whichthe supports E are arranged inwardly of the ends of the blades, beingformed, preferably, with inclined bearing-faces h, which are engaged bythe nuts 9 on the stays G.

Figs. 7 and 8 illustrate a modified construction of Figs. 5 and 6 inthat the supports are arranged interiorly of the fan-blades and engagethe inner edges of the blades. The flanges b are here formed on theinner edges of the blades and are riveted to the supports in the mannerbefore described.

In the construction shown in Figs. 9 and 10 the supports E E arearranged on theouter edges of the blades inwardly of their ends in amanner similar to the construction shown in Figs. 5 and 6. In this caseloose triangular blocks it may be placed on the supports E E to formbearing-faces for the nuts 9 of the stays G. The spaces or ports betweenthe bladesB are shown as closed by the supports E the latterconstituting flat rings arranged at the ends of the blades. The bladesin this case are preferably formed with square ends which are formedwith suitable flanges W, by which they are connected to the rings E byrivets, as shown. While ordinarily I prefer that the ports between theblades should be open, yet when operating upon a heavy fluid, as water,I find that the construction just described is advantageous, because theends of the blades are thus strongly and rigidly supported.

It is essential that the fan-blades shall be adapted to carry the fluidwith them rotatively, so that it shall be thrown outward by centrifugalforce and be discharged tangentially in contradistinct-iou to merelyexerting a wedge-like action upon the fluid, tending to thrust itoutward in radialdirection unaccompanied by any material rotation orwhirling of the fluid. In a true centrifugal fan it is almost solely therear surface of the blade which acts upon the fluid, drawing it aroundby suction,whereas in blades which thrust the fluid outward by awedge-like action it is the front or advancing side of the blade whichis the active face. Blades of the latter kind require to be inclined orcurved rearwardly to a considerable angle, so that the outer edgefollows behind the middle or major portion of the blade. I use theexpression in transverse section arranged relatively to the axis anddirection of rotation to carry the fluid with them rotatively anddischarge it tangentially to exclude such rearwardly-inclined or wedgingblades and include generically any form of blade adapted to act upon theair by rotating or whirling it, thus including blades which aresubstantially radial as well as those which incline forwardly and eitherfiat, curved, or angled.

The operation of the fan shown when propelling air is accompanied by theexistence of a thin shell or film of rapidly-whirling air immediatelysurrounding the drum-like series of blades,which airis apparentlycompressed, and outside of this shell the air discharging from the fanescapes tangentially. Whether the fan is provided with a casing or notthe construction must be such as to permit the whirling fluid dischargedfrom the blades to escape tangentially therefrom in outward direction.

7 It is practically essential that the whirling fluid discharged fromthe fan-blades shall be permitted to escape tangentially outwardtherefrom, as any attempt to divert the revolving fluid inwardly resultsin a rapid diminution of efficiency; but the whirling fluid can becollected in a casing, and if the outlet from this casing be arrangedbeyond the radius of the circle described by the outer edges of theblades the fluid will freely escape through said outlet, its whirlingmotion being thereby resolved into a direct motion, after which it canbe led through a suitable conduit in any desired direction.

I claim as my invention the following-defined novel features,substantially as hereinbefore specified, namely:

1. A centrifugal fan or pump, comprising a rotary member having numerouselongated blades arranged lengthwise in approximately axial direction,and in substantially drum form, so as to inclose within them arelatively large and practically unobstructed intakechamber, and intransverse section arranged, relatively to the axis and direction ofrotation, to carry the fluid with them rotatively and discharge ittangentially, said rotary IIG &

member being open at both ends, so that the fluid operated on may betaken in axially through both ends thereof, and having a hub,

annular supports engaging the outer edges of said blades and adjustablestays connecting said supports with said hub, and a means for somounting said rotary member as to permit the tangential escape of thefluid discharged from said blades.

2. A centrifugal fan or pump, comprising a rotary member having numerouselongated blades arranged lengthwise in approximately axial direction,and in substantially drum form, so as to inclose Within them arelatively large and practically unobstructed intakechamber, and intransverse section arranged, relatively to the axis and direction ofrotation, to carry the fluid with them rotatively said supports withsaid hub, and a means for 1 so mounting said rotary member as to permitthe tangential escape of the fluid discharged from said blades.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

SAMUEL OLELAND DAVIDSON.

Witnesses:

HUGH TAYLOR COULTER, ARTHUR O. FRASER.

